Die cutting process

Die before pressing, according to product design requirements, with a steel knife (that is, die cutting knife) mouth copper wire (that is, die pressing knife) or steel die into die cutting indentation version (referred to as die pressing version), the die pressing version installed in the die pressing machine, under the pressure of the cardboard rolling cut molding and press out folding line or other die lines. Die plate structure and working principle, circular die cutting, flat die cutting. Die - cutting indentation of the main process and operation process

Steel knife rolling cutting, is a shearing process; And copper wire or steel die on the pressure of cardboard deformation: elastic rubber strip (or sponge) used to make the finished product or waste easily separated from the cutting edge pad version of the role of cutting board.

Fault analysis and analysis

1 die cutting precision is not high

Deviation in die cutting is the most common problem in production. Die cutting precision is one of the most important standards to measure the quality of die cutting, is an important guarantee of qualified products. There are many reasons that affect the precision of die cutting, such as mechanical reasons, die cutting version itself, but also from the problem of printed matter, operating environment, personnel problems, etc. There are different solutions to different problems, and here they are analyzed one by one.

■ cardboard transmission process, the main transmission chain wear elongated, will directly affect the positioning accuracy before die-cutting, die-cutting operation to replace the chain in figure 4. Intermittent mechanism wear, causing tooth row in the stop or start process jitter, will also affect the precision of die cutting. In this case, it will only affect the positioning accuracy. At this time, the agency should be overhauled

■ front and rear positioning frame positioning distance is too small. Because the length of the chain itself has a certain error, if the positioning distance is too small, before and after positioning can not eliminate the chain error, thus affecting the precision of die cutting. At this time should adjust before positioning swing frame adjustment screw or after positioning swing frame CAM position, so that before and after positioning frame can move tooth row 2mm ~ 3mm distance is appropriate

- on the die - cutting version or die - cutting version positioning is not accurate. Long time use of the machine will cause die cutting plate or die cutting bottom plate positioning block wear, so that the fit gap is too large and lead to die cutting accuracy. The positioning block should be replaced at this time. The wear of the side positioning plate is an important factor for inaccurate side positioning. As the amount of positioning motion is not enough to make up for the good wear, the side positioning accuracy will become worse. At this point, the side positioning plate should be replaced

B paper teeth pressure is too small or uneven. If the flexible tooth elasticity of the paper teeth due to long-term use and small, will cause the paper in the transfer process of slip or fall off, thus directly affecting the precision of die cutting; Paper teeth between the pressure may cause uneven paper in the die - cutting process. The removable teeth should be replaced at this time. In addition, the fixed teeth should be consistent in the horizontal height, or it may be in the paper in the paper collision or paper after the paper wrinkle, affect the precision of die cutting;

The above points are mainly mechanical factors, the need for maintenance personnel to do a good job in the maintenance of the machine, timely inspection and maintenance of parts, and replacement of wear accessories, to ensure the best state of die-cutting machinery.

■ plate problem. If there is a problem in the process of design plate making, you should choose the advanced plate making method, improve the precision of die cutting; Or to correct the template, mainly printing and die - cutting position. Manual plate making is prone to deviation, may make the printing position and die cutting position is not consistent, if necessary, need to make a new template;

■ environmental impact. Mainly is the cardboard deformation or stretching, resulting in "overprinter" is not allowed, thus affecting the precision of die cutting. Try to ensure die cutting indentation and printing in the same working environment or ensure the identity of the working environment (g port has the same temperature, humidity, etc.). Glazing and film coated sheets to die - cutting pretreatment, minimize the impact of paper deformation liu die - cutting accuracy. Should choose appropriate paper, reduce the impact of material defects on die-cutting accuracy

■ influence of operator. This includes the entire production process from plate making to printing die cutting, requiring operators to operate strictly in accordance with the process flow, improving production management requirements, and training operators in professional skills when necessary.

Die - cutting version and paste version

The so-called loose plate, refers to die - cutting scrap and cardboard spread out and cause the paper. Loose plate will affect die - cutting and board transfer, thus affecting the normal production. The main cause of the loose plate is die cutting plate making process errors and elastic rubber (or sponge) when the choice; At the same time, other factors may also contribute to the fragmentation. Die - cutting "paste version" refers to the board adhere to the die - cutting version, can not be separated in time.

B plate - making reasons. Making die cutting, on the shape of complex products or the same version of the arrangement of live pieces too much, and set up in the die cutting point is very small, very few, it is easy to cause the die cutting. At this point should be appropriate to increase the number of points, should try to live parts length direction and cardboard transfer direction to maintain the same. Die - cutting version of the elastic strip (or sponge) is too soft, you can not smooth up the board, will also cause loose. At this time should choose high hardness, good elasticity of high quality elastic rubber (or sponge);

■ flat die cutting. Pressing too early to start is also an important cause of loose plate. Die cutting, when moving the platform down, although the paper has been elastic rubber strip (sponge) bounce off the knife line, but because of elastic rubber strip (sponge) generally higher than the knife line 2mm -- 3mm, at this time if the tooth row in its paper began to move, will be due to the elastic rubber strip (sponge) is still pressed on the board die cutting bottom plate and easy to tear, resulting in loose. At this time should loosen the secrest mechanism and the main sprocket shaft coupling sleeve for adjustment, so that the moving platform from the top dead center down 10mm ~ 15mm(paper cutting control at about 7mm - 8mm), the press began to move;

■ material problems. If the paper board is too bad, fiber is too short, you may appear in the die - cutting process. Can appropriately reduce the speed of die cutting, in the making of plates to pay attention to increase the number of points, produce paste version of the main reason is that the die cutting knife around the elastic strip too thin or hard too small, back elastic; Die cutting edge is not sharp, paper too thick, caused by clamping or die cutting stick knife. According to the distribution of die cutting knife, choose different hardness of the sponge and reasonable arrangement of its position or replacement die cutting knife.

3 die cutting edge is not smooth, fluff

The main reason for this phenomenon and the quality of the steel knife and die cutting pressure, there are mainly the following cases, can be solved according to the actual situation.

■ bad quality of steel knife, cutting edge is not sharp, die - cutting suitability is poor. This is the main cause of blade not smooth or even fluff. According to the die cutting printing crystal of different properties to choose a steel knife, improve its die cutting fit, no special requirements; Under the condition, try to choose the steel knife with horizontal grain treatment;

■ steel blade is badly worn and not replaced in time. Often check the cutting edge of steel knife wear, found wear and affect the quality of die cutting, timely replacement of a new steel knife;

■ die cutting pressure adjustment, steel knife pad paper improper treatment, causing die cutting pressure discomfort, will also produce edge not smooth or fluffiness. Can re-adjust the die cutting pressure and replace the pad paper, so that the pressure meets the requirements of die cutting, in the replacement of steel blade should pay attention to timely replacement pad paper;

Die - cutting version production improper. Die cutting knife and elastic rubber strip (or sponge) matching and installation is not standard, will also cause the above phenomenon. Elastic rubber strip (or sponge) hardness to be appropriate, different products should choose different hardness of the elastic rubber strip (or sponge), at the same time, the position and height of placement must also meet the specifications;

■ blade is not smooth or fluff generation, and the flatness of the bottom plate and machine pressure. The bottom plate must be flat and replaced if necessary.

4 burst wire (dark wire)

Breaking line refers to the product in die cutting or finished product folding, cardboard die cutting pressure is too large, exceeding the cardboard fiber bearing limit, so that the indentation of the cardboard fiber fracture or partial fracture. "Dark line" refers to the indentation line should not be. This is often die cutting problems, especially in dry weather, often occur. It should be analyzed on a case-by-case basis.

■ die cutting pressure is too high. Adjust the pressure of the die - cutting machine, make the waste edge just separate. Board thickness is too large, die - cutting steel line height selection to be reasonable, the plate under the pad paper to appropriate increase or decrease, in order to get the best pressure. Folding molding, such as cardboard indentation outside cracking, the reason is too deep indentation or indentation width is not enough: if the cardboard inside cracking, for the mold indentation force is too large, folding too deep. Can reduce the thickness of steel wire cutting; Widen the indentation line according to the thickness of the board; Reduce the pressure of the die cutting machine; Or use steel wire with a lower height;

■ low water content of the board, resulting in paper flexibility to become brittle breaking line. Especially after high - temperature polishing paper, die - cutting more explosive line. Should increase the humidity of the workshop environment or before die cutting the cardboard placed in the workshop moisture, can also be used to the back of the paper water, increase its water content, make it flexible, then on the die cutting machine. Paper fiber direction and die - cutting version row knife direction to keep consistent;

■ printing surface with large areas of deep color field, die - cutting prone to explosive color, explosive line. Printing in the dark ink without or less add ink additives, to strengthen the adhesion of ink on paper, can reduce the phenomenon of burst color, burst line. The accumulation of paper powder from the incision in the groove can also affect production. Operators should be timely clean up paper disputes, foreign bodies, etc.

In die-cutting hard box cigarette packet small box, because of many positions of the indentation line between the distance is very close, if the normal configuration of indentation steel line height, the pressure on the paper when the tension is too large, will also cause a burst. Therefore, we should try to minimize the tension on the paper. One is to reduce the height of the indentation steel line: the second is to reduce the indentation bottom die strip thickness, both can not be used at the same time, or not good indentation effect. A better method is to reduce the height of the indentation steel line, usually by 0. 1 mm - 0. 2 mm. According to the thickness of the paper to determine how much.